This invention relates to a tape driving device suited to, for example, a video signal recording and reproducing apparatus of stationary head type, and more particularly to a device having an improved loading mechanism for loading an endless tape.
Generally, a tape driving device for use in the video signal recording and reproducing device, i.e., a video tape recorder (which is hereinafter referred to as "VTR") is constructed such that a pinch roller formed of, for example, rubber is pressed, through an endless tape, against the peripheral surface of a capstan being rotated by a motor and the tape is allowed to travel through rotation of the capstan. In this tape driving device, in order to stably record and reproduce a video signal, the tape usually is pressed on a magnetic head by a tape guide facing the head.
The above-mentioned pinch roller and tape guide desirably are movably so provided that when the tape is loaded, interspaces each permitting an easy insertion of the tape thereinto are formed between the pinch roller and the capstan and between the tape guide and the head. Therefore, a pinch roller driving mechanism for permitting the pinch roller to abut against and to be a part from the capstan, and a tape guide driving mechanism for permitting the tape guide to abut against and to be apart from the head usually are separately provided, and independently or interlockingly operated. However, such a tape loading means wherein said two mechanisms are separately provided not only has the drawback that it is made complicated in construction with the result that the manufacturing cost is increased, but also should be manufactured with an extremely high precision. The reason for the latter disadvantage is that in the case where a variation occurs in the distance between each one of said mechanisms and the surface of a substrate, that is the horizontal or vertical degree of each said mechanism relative to the substrate surface, or the movable range of each said mechanism, the pinch roller and tape guide fail to uniformly contact with the travelling tape to make the tape travel unstable. Particularly for the stationary head type VTR requiring a long endless tape to travel at a high speed of, for example, 10 m per second the presence of even a small eccentricity or displacement in each said mechanism causes a great decrease in the stability of the tape travel. Therefore, said tape loading means have to be manufactured with a sufficiently high precision. Further, the unevenness of tape travel, that is, wows and flutters appear in a picture of the VTR in the form of jitters. One of the reasons why the stationary head type VTR has not yet been put to practical use is that the high-speed travel of the endless tape is followed by the occurrence of too many wows and flutters.